This invention relates to a radiator which is for radiating heat generated by an electronic component upon energization to prevent an increase in temperature of the electronic component and which is attached to the electronic component itself or to a circuit board or a housing with the electronic component mounted thereon.
In the field of electronic communication, use is made of electronic apparatuses and data processing apparatuses with various electronic components mounted thereon. These electronic components are generally mounted on a circuit board provided with a conductive pattern.
These electronic components may be various semiconductor active devices including a random access memory (RAM), a read-only memory (ROM), a microprocessor (MPU), a central processing unit (CPU), and an image processor arithmetic logic unit (IPALU). Generally, these semiconductor active devices are used at a high frequency and operated at a high speed. To this end, the semiconductor active devices are highly integrated in accordance with a circuit layout and provided with a plurality of terminals (generally called a lead frame) for use in signal processing to be formed into a chip of a semiconductor integrated circuit device (IC) or a semiconductor large-scale integrated circuit device (LSI).
The semiconductor active device of the type described has an operation speed and a signal processing speed each of which is very high. In order to perform a high-speed operation with a further integrated structure, the device is designed to be used at a high frequency in a frequency band between several tens MHz and several GHz. Accordingly, a radiator attached to the semiconductor active device is required to be further improved in radiation efficiency.
In the meanwhile, if such a high frequency within the frequency band between several tens MHz and several GHz is used at the semiconductor active device, a high-frequency (harmonic) current flows through the terminals of the semiconductor active device and the radiator itself. The high-frequency current may be conducted to other electronic components, signal paths including the terminals, or apparatuses and devices with the electric/electronic components mounted thereon. The high-frequency current becomes a factor of causing electromagnetic interference which adversely affects the operation of the electronic components to result in an operation error or which deteriorates basic functions of the electronic components. Therefore, such high-frequency current must be removed or suppressed.
In existing electronic components or radiators, however, consideration is not sufficiently made of the countermeasure against the high-frequency current. Therefore, it is difficult to prevent the occurrence of the electromagnetic interference resulting from the high frequency current.
It is therefore an object of this invention to provide a radiator of a high-frequency current suppressing type which is capable of sufficiently and considerably suppressing a high-frequency current to prevent occurrence of electromagnetic interference even if an electronic component is used at a high frequency within a frequency band between several tens MHz and several GHz.
Other objects of the present invention will become clear as the description proceeds.
According to an aspect of the present invention, there is provided a radiator for use in radiating heat generated by an electronic component, the radiator having a principal surface facing the electronic component, the radiator comprising a high-frequency current suppressor attached to the principal surface for attenuating a high-frequency current flowing through the radiator and having a frequency within a frequency band between several tens MHz and several GHz.
According to another aspect of the present invention, there is provided a radiator for use in radiating heat generated by an electronic component, the radiator having a principal surface facing the electronic component, the radiator comprising a high-frequency current suppressor attached to the principal surface for attenuating a high-frequency current flowing through the radiator and having a frequency within a frequency band between several tens MHz and several GHz and a heat-conductive sheet excellent in heat conductivity and formed on the high-frequency current suppressor.
According to still another aspect of the present invention, there is provided a radiator for use in radiating heat generated by an electronic component, the radiator having a principal surface facing the electronic component, the radiator comprising a high-frequency current suppressor attached to the principal surface for attenuating a high-frequency current flowing through the radiator and having a frequency within a frequency band between several tens MHz and several GHz and an insulating sheet excellent in electrical insulation and formed on the high-frequency current suppressor.
According to yet another aspect of the present invention, there is provided a radiator for use in radiating heat generated by an electronic component, the radiator having a principal surface facing the electronic component, the radiator comprising a high-frequency current suppressor attached to the principal surface for attenuating a high-frequency current flowing through the radiator and having a frequency within a frequency band between several tens MHz and several GHz, the high-frequency current suppressor being made of a magnetic substance of a magnetic composition comprising M, X and Y, where M is a metallic magnetic material consisting of Fe, Co, and/or Ni, X being element or elements other than M and Y, and Y being F, N, and/or O, the Mxe2x80x94Xxe2x80x94Y magnetic composition having a concentration of M in the composition so that the Mxe2x80x94Xxe2x80x94Y magnetic composition has a saturation magnetization of 35-80% of that of the metallic bulk of magnetic material comprising M alone, the magnetic composition having the maximum value xcexcxe2x80x3max of an imaginary part xcexcxe2x80x3 of relative permeability in a frequency range of 0.1-10 gigahertz (GHz).